Instrument lighting fixtures



' 1958 M. K. LAUFER ETAL 2,846,567

INSTRUMENT LIGHTING FIXTURES Filed Aug. 8, 1956 2 Sheets-Sheet 1 52 Mala 32 Hay I2 IO Q 0 0 I 'o o 48 A ra 4s '30 (Q1 o OA 8 24 I 22 0 0 $0 I INVENTORS MAURICE K.LAUFER WILLIAM D.HALL

Z/JJVW IL ATTORNEYS Aug. 5, 195 M. K. LAUFER ET AL INSTRUMENT LIGHTING FIXTURES Filed Aug. 8, 1956 2 Sheets-Sheet 2 FijI INVENTORfi MAURICE K.LAUFER WILLIAM D. HALL MW; @M/Mw;

ATTORNEY5 msrnnrvi u'r rronrmo rrrrrunns lidauree K. Laufer William D. Hall, Urbana, Shin, assignors to Grimes Manufacturing {Sump-any, Urbana, Fabio, a corporation of Qhio Application August 8, 1956, Serial No. 602,752

9 Claims. (Cl. 24ll-8.16)

The present invention relates to an instrument lighting fixture and, more particularly, to a light assembly and li hting fixture adapted for use in vehicular instrument panels, such as aircraft or the like.

in our cor-ending United States application, Serial No. 535,808, May 18, 1956, and entitled instrument Lighting Fixtures, a lighting fixture was disclosed with a light assembly which directed the light rays onto theface if an instrument from the periphery of the instrument downwardly at an angle to the face of the instrument. In certain types of instruments used in air-craft, it is desirable that only the borders of the face of the instrument be directly lighted, the remaining portion of the instrument face being lighted indirectly through the transmission of light from the borders of the instrument face. A turn and bank indicator which has a ball movable through a curved transparent tube filled with a liquid can be lighted by applying light directly to the ends of the curved tube. the light then being transmitted merely along the curved tube. in other cases it has been found desirable to have the lighting fixture with light bulbs mounted therein in such a manner that light transmitted from the fixture will substantially along the surface of the instrument face rather than directed downwardly and inwardly toward the instrument face. By providing an instrument fixture which emits light substantially along the face of t..e instrument, the chance of reflection from the face of the instrument into the pilots eyes is materially reduced.

An object of the present invention is to provide a lighting fixture for use with individual instruments which is rl extremely small size, fits the face of the instrument ml permits close instrument spacing.

Another object of the present invention is to provide a lighting fixture for individual instruments, the lamp bulbs of the lighting fixture being so positioned that their filament ends are substantially adjacent to the instrument face.

A still further object of the present invention is to provide a lighting fixture with improved means for mounting a lamp bulb therein, the means permitting easy removal and replacement of the bulb.

Still another object of the present invention is to provide a lighting fixture including lamp bulbs which have the' filament end so positioned as to transmit light substantially along the surface of the instrument face.

Still another object of the present invention is to provide a lighting fixture utilizing extremely small lamp bulbs which are of the peanut type, the contacts for the bulbs being positively made and not affected by the usual vibration of an instrument panel.

These and other objects of the resent invention will appear more clearly in the following specification, claims and drawings, in which:

Figure l is a front elevational view of the lighting fixture of the present invention mounted on an instrument in an instrument panel;

Figure 2 is a side elevational view of the lighting fix- 234 5 56? l atented Aug. 5, 1%58 ture in Figure l, the instrument panel being shown in section;

Figure 3 is a view similar to Figure 2 but showing the lighting fixture and instrument partly in vertical section;

Figure 4 is a rear elevational view of the lighting fixture showing the back plate in detail and omitting the instrument panel and instrument;

Figure 5 is an enlarged vertical section through one of the light assemblies of the present invention;

Figure 6 is a fragmentary view looking down into the socket with the cup-shaped housing member and lamp bulb removed; and

Figure 7 is an enlarged exploded view of the lamp bulb mounting means.

Referring now to the drawings wherein like character or reference numerals represent like or similar parts, the lighting fixture of the present invention is shown mounted in an instrument panel 10 of an aircraft or other vehicle. In more detail, an instrument "12 having a flanged portion 14 is front-mounted in the instrument panel by means of bolts 16 passing through holes in the outer confines of the four corners of the instrument flange and through holes in the instrument panel. The instrument 10 is a turn and bank instrument of the type having an upper indicator element is for determining the amount of turn and a lower indicator element 20 for determining: the amount of bank. The lower indicator element 2i} includes a curved, hollow transparent glass tube 22 filled with a suitable liquid and a ball element 24 mounted for movement within the glass tube.

The instrument 12 is provided with a bezel 26 which retains its glass face 23 and provides a surface to mount the lighting fixture of the present invention. The light-- ing fixture of the present invention includes a cover member generally indicated by the numeral 39, the cover member being adapted to be detachably mounted on the face of the instrument as described in detail in our aforementioned copending United States application,v Serial No. 585,800.

In more detail, the upper bolts 16 which hold the instrument 12 to the instrument panel also hold a clamp member 32. The lower bolts 16 are adapted to be inserted through suitable holes in the lower corners of thecover member 30, as well as through holes in the flange of the instrument and the instrument panel ill. The cover member 3%) may be removed by merely removing the lower bolts and sliding the upper edge of the cover member from under the bracket 32.

As best shown in Figures 1 and 3, cover member 3% is provided with a back plate 34 and a front plate 36 spaced from but rigidly secured to the back plate by means of rivets 38. The front and back plates 36 and 34 respectively are provided with apertures 40 and 42 respectively (Figure 4), the apertures being of such size and shape as to expose the face of the turn and bank in dicator or instrument 12. Back plate 34 and front plate 36 are provided with overlapping flanged outer edges 44 (Figure 3) so as to mask the light from being transmitted laterally outwardly between the back and front plates. Referring specifically to Figure 4, the back plate 34 is provided with a cut-out portion 46 on each side of the aperture 42, the cut-out portions being oppositely disposed from each other and on each side of a vertical median through the instrument face. When the cover member 30 is positioned on the instrument 12 as shown in Figure 1, the cut-out portions 42 lie adjacent to the ends of the curved tube 22. Front plate 36 along the edges of its aperture 40 is beveled downwardly and inwardly, as indicated at 48, the beveled portion terminating in a plane substantially parallel to the plane of the back plate 34. The beveled portions 48 are light-impervious and prevent the rays of light from a pair of light assemblies 50 from being transmitted laterally inwardly from between the front and back plates. In other words, the light from the light assemblies 50 will travel only through the cut-out portion 46 directly onto the face of the instrument adjacent the ends of the curved tube 22. A more detailed description of this feature of the invention will be discussed more fully later in the specification.

A pair of light assemblies 52 are mounted on the front plate 36 of cover member 30 at the outer extremities of its upper corners. Light assemblies 52 are of the type disclosed in our aforementioned copending application, Serial No. 585,800, and are provided with lighttransmitting slots for transmitting the rays of light from a lamp bulb mounted therein with its filament end away from the face of the instrument dial. The light emitted from light assemblies 52 is directed downwardly and inwardly toward the upper portion of the face of the instrument dial and, thus, direct light rays are shielded from the pilots eyes.

Referring more specifically to the light assemblies 50, and in particular to Figures 3, 5, 6 and 7, it will be noted that an apertured socket 54 is provided in the front plate 36 of cover member 30. Socket 54 is integrally formed in the face plate 36, as indicated at 56, in any other suitable manner. The socket 54 is provided with internal threads 58 which are adapted to receive external threads 69 of a cup-shaped housing 62. Housing 62 is adapted to support a lamp bulb 64 with its filament end extending inwardly toward the instrument face. Lamp bulb 64 is provided with a cylindrical contact 66 and a center contact 68, the center contact adapted v to engage a coil spring terminal 70 mounted centrally of and within the cup-shaped housing 62.

An annular gasket member 72 slipped over the filament end of lamp bulb 64 and positioned on the cylindrical contact 66 is provided for centrally supporting the lamp bulb within the housing 62. In more detail, the annular gasket 72 is made of an insulating material such as rubber, synthetic rubber, plastics, or the like. After it is positioned on the bulb 64, the bulb is then slid into the housing 62 and the gasket 72 will frictionally retain the bulb in the housing, as well as center it so that its center contact 68 is spaced from the walls of the housing. To make it easier to slide the bulb and the gasket member 72 into the housing 62, the gasket member is provided with longitudinally extending ribs 74, the ribs providing less contact surface with the walls of the cupshaped housing 62. Further, it will be noted from Fig ures and 7 that the annular gasket 72 is of less length than the length of the cylindrical contact 66, the purpose of making the gasket of less length is to have a portion of the cylindrical contact 66 adjacent the filament end of bulb 44 exposed so that it may contact a terminal 76, as will be explained more fully hereinafter.

Mounted between front and back plates 36 and 34, respectively, and adjacent each of the socket members 54, is a tubular insulator member 78 shown in Figure 5. The tubular insulator member 78 is made of a transparent plastic material and may be suitably colored to filter the light from lamp bulb 64. The tubular member 78 extends upwardly and centrally of the socket 54 and supports at its upper end the arcuate-shaped terminal 76. Terminal 76 is connected by a current conducting means 80 such as a wire to a suitable source of electrical energy. Light rays from the lamp bulb 64 are transferred through the walls of tubular member 78 and through the slot 46 in back plate 44 onto the ends of the curved tube 22. The light will then travel through the curved tube lighting the path in which the ball 24 moves.

By having the lamp bulb 64 with its filament end positioned between the front and back plates 36 and 34 respectively, a compact light assembly is provided and the light can be emitted directly to the face of the instrument so that there will be no glare reflected back to the pilots eyes. When the lamp bulb 64 burns out, it is a simple matter to replace the same, as it is merely necessary to unscrew the cup-shaped housing 62 from the socket 54 and the lamp bulb will be removed therewith. The lamp bulb can then be taken out of the housing and replaced by another bulb as explained above. The housing 62 with the new bulb in place is then repositioned in the socket 54. The ground for the light assembly is through the center contact 68, coil spring 70, cup-shaped housing 62, socket 54, cover member 30, instrument 12, and instrument panel 10.

It is preferable that each of the light assemblies 50 and 52 be connected in parallel so that should any bulb burn out, the other bulbs will remain lighted.

The terminology used in the specification is for the purpose of description and not limitation, the scope of the invention being defined in the claims.

We claim:

1. In an instrument lighting device for use in an instrument mounted in an instrument panel, a cover member adapted to fit around at least a portion of the periphery of the instrument face, means to detachably mount said cover member on the instrument panel, said cover member including a back plate and a front plate secured to and spaced from said back plate, said back and front plates having a light impervious wall therebtween at least around the outside of said cover member and a lighttransmitting opening positioned adjacent the periphery of the instrument face, a lamp bulb having a cylindrical and a center contact, a tubular element positioned between said front and back plates adjacent said light-transmitting opening, said tubular element being made of an insulating material and including an arcuate-shaped terminal therein at its end which is adjacent the front plate, said terminal being insulated by said tubular element from said front and back plates, current conducting means extending from a power supply and connected to said arcuate-shaped terminal, a socket positioned in said front plate adjacent said tubular insulating element, a cupshaped housing, means to detachably support said cupshaped housing in said socket, means frictionally supporting said lamp bulb by its cylindrical contact in said housing so that when said cup-shaped housing is detachably supported in said socket the lamp bulb is supported with its filament end in said tubular element and its cylindrical contact engaging said arcuate-shaped terminal, said last mentioned means insulating the cylindrical contact of said lamp bulb from said housing, and means to ground the center contact of said lamp bulb to said cup-shaped housing.

2. A lighting device of the character described in claim 1 wherein said means to detachably support said housing in the socket of said front plate includes internal threads in said socket and external threads on said housing.

3. An instrument lighting device of the character described in claim 1 wherein the means to support and insulate said lamp bulb in said housing includes an annular gasket having a longitudinal thickness less than the length of the cylindrical contact of the lamp, the annular gasket being positioned on the cylindrical contact adjacent the base of the lamp whereby the arcuate terminal may engage the portion of the cylindrical contact adjacent the filament end.

4. An instrument lighting device of the character described in claim 3 wherein said annular gasket is provided with circumferentially spaced longitudinal ribs on its outer surface, the ribs permitting a minimum contact with the inner wall of said cup-shaped housing.

5. In combination, an instrument panel, an instrument mounted on said instrument panel, a cover member adapted to fit around and cover a portion of the face of the instrument, said cover member including a substantially planar apertured back plate having a cutout portion on its inner apertured edge and a front plate secured to and spaced from said back plate, said front plate being apertured and provided with a light-impervious projection extending inwardly to the plane of the rear plate adjacent the cut-out portion, a lamp bulb having a cylindrical contact and a center contact, means for mounting said lamp bulb on said front plate with its filament end extending inwardly between said front and back plate, said last mentioned means being positioned adjacent said light-impervious projection and holding said lamp bulb in a position to emit rays through said cut-out portion onto the instrument face perpendicular thereto.

6. In combination, an instrument panel, an instrument mounted on said instrument panel, a cover member adapted to fit around and cover a portion of the face of the instrument, said cover member including a substantially planar apertured back plate having a cut-out portion on its inner apertured edge and a front plate secured to and spaced from said back plate, said front plate being apertured and provided with a light-impervious projection extending inwardly to the plane of the rear plate adjacent the cut-out portion, a lamp bulb having a cylindrical contact and a center contact, a tubular element positioned between said front and back plates and adjacent the cut-out portion, said tubular element being made of a light-transmitting insulating material, a socket in said front plate adjacent said tubular member, an arcuate-shaped terminal mounted in said tubular member adjacent the socket, said terminal being insulated by said tubular member from said front and back plate, current conducting means connected to a source of power and to said arcuate-shaped terminal, a cup-shaped housing adapted to be detachably supported by said socket, said lamp bulb being supported in said cup-shaped housing with its filament end and a portion of its cylindrical contact extending into said tubular element, the portion of said cylindrical contact extending into said tubular element contacting said arcuate-shaped terminal, means frictionally supporting said lamp bulb in said cup-shaped housing so that when said housing is removed from said socket said lamp bulb is also removed and to insulate its cylindrical contact from said cup-shaped housing, and means in said cup-shaped housing engaging said center contact to provide a ground for said lamp bulb.

7. A combination of claim 6 wherein said means to mount said lamp bulb in said cup-shaped housing includes a resilient annular gasket positioned on the cylindrical contact of said lamp bulb adjacent its base end.

8. The combination of the character described in claim 7 wherein said annular gasket is provided with longitudinally extending and circumferentially spaced ribs for engagement with the walls of said cup-shaped housing.

9. In combination, an instrument panel, an instrument mounted on said instrument panel, a cover member adapted to fit around and cover a portion of the face of the instrument, said cover member including a substantially planar apertured back plate having a pair of diametrically opposed cut-out portions on its inner apertured edge and a front plate secured to and spaced from said back plate, said front plate being apertured and provided with diametrically opposed projections on its inner apertured edge adjacent each of said cut-out portions and extending inwardly toward and terminating in the plane of the rear plate, said cut-out portions in said back plate providing means to direct light rays onto the face of said instrument in a direction substantially perpendicular thereto, a light assembly supported in said cover member adjacent each of said cut-out portions, said light assemblies each including a tubular element positioned between said front and back plates and adjacent the cut-out portion, said tubular element being made of a light-transmitting insulating material, a socket in said front plate adjacent said tubular member, an arcuateshaped terminal mounted in said tubular member adjacent the socket, said terminal being insulated by said tubular member from said front and back plate, current conducting means connected to a source of power and to said arcuate-shaped terminal, a cup-shaped housing adapted to be detachably supported by said socket, a lamp bulb having a cylindrical and center contact, said lamp bulb being supported in said cup-shaped housing with its filament end and a portion of its cylindrical contact extending into said tubular element, the portion of said cylindrical contact extending into said tubular element being in contact with said arcuate-shaped terminal, means frictionally supporting said lamp bulb in said cup-shaped housing so that when said cup-shaped housing is removed from said socket said light bulb is also removed and to insulate its cylindrical contact from said cup-shaped housing, and means in said cup-shaped housing engaging said center contact to provide a ground for said lamp bulb.

References Cited in the file of this patent UNITED STATES PATENTS 2,202,155 Kollsman May 28, 1940 2,247,409 Roper July 1, 1941 2,518,726 Shlenker Aug. 15, 1950 2,614,205 Roper et al. Oct. 14, 1952 2,637,802 Roper et al. May 5, 1953 2,710,910 Grimes June 14, 1955 

